Rustins Professional Wood Filler Natural is a two-part filler that provides a strong, long-lasting repair for all interior and exterior woodwork. It hardens within 30 minutes at ambient temperature, producing a tack-free surface. This filler is easy to sand and readily accepts Rustins Wood Dyes, paints, and varnishes. Once fully hardened, it can be sanded, drilled, machined, and planed, making it particularly useful for repairs to joinery edges where high strength is needed. It is also suitable for marine applications.